Valve housings are often made from parts which are machined, e.g. from brass material. Other parts of the valve, such as connectors and actuator casings, may be made from a material which is different from the material of the valve housing. Accordingly, various parts of the valve are assembled either by means of soldering or by means of mechanical connections, such as screw connections including a sealing member, such as a gasket and/or an o-ring.
In the case that a soldering technique is used, heating of the entire valve is required, and this has the consequence, that only materials which are able to withstand the required temperatures can be used for any parts of the valve. For instance, this rules out the use of plastic parts.
In the case that mechanical connections are used, there is a risk of leaks occurring in the valve. This is particularly an issue if the valve is operated at high pressure levels.
U.S. Pat. No. 8,136,543 B2 discloses an axial flow control valve including a valve body defining a passageway between an inlet and an outlet that is substantially parallel to a fluid flow path at the inlet and the outlet of the valve body. The control valve includes a cartridge assembly removably coupled to the valve body and disposed within the passageway of the valve body between the inlet and the outlet. The cartridge assembly is substantially axially aligned with the passageway and includes a motor to operate the axial flow control valve between a first position to prevent the flow of fluid between the inlet and the outlet and a second position to allow the flow of fluid between the inlet and the outlet.
EP 0 232 858 A1 discloses a retention valve for liquid-bearing conduits, comprising a containment body provided with threaded sleeves for connecting to conduits, and, in its interior, with valve means suitable for cutting off the flow of a liquid. The containment body is provided in two parts of pressed sheet metal, which may be connected by a tungsten inert gas (TIG) or the like circumferential welding. The retention valve is a passive or pressure controlled valve. Accordingly, no actuator is present for controlling the valve.
US 2014/0197347 A1 discloses a valve arranged inside a body cavity portion. A tapered inlet portion is welded onto the body cavity portion. An actuator is arranged exteriorly with respect to the body cavity portion.
WO 2014/072715 A1 discloses a motorized sleeve valve including a valve body defining a first fluid port and a second fluid port and a valve sleeve surrounding at least a portion of the valve body. An electric motor configured to actuate the valve sleeve is arranged inside a tubular shroud surrounding the sleeve valve.
EP 2 653 758 A1 discloses an axial valve comprising an actuator. The movable valve parts and the actuator are arranged inside a valve housing formed in one piece.